Commissioning of a higher harmonic RF system for the Advanced Light Source

We report on the commissioning of a higher harmonic RF system designed to improve the Touschek lifetime of the Advanced Light Source. In our best results, we have achieved over a factor of two increase in the beam lifetime. Transient beam loading of the harmonic cavities by unequal fill patterns presents the greatest limitations on lifetime improvement. We also describe several interesting effects of the harmonic cavities on the operation of the longitudinal and transverse multibunch feedback systems.